The present invention relates to filtering control of a portable electronic device such as that capable of performing wireless communications, and more particularly, to a frequency tunable filter and an associated apparatus.
According to the related art, a conventional portable electronic device such as a multifunctional mobile phone may be designed to have the capability of performing wireless communications based on various well-developed and well-defined wireless communications technologies (e.g. Global System for Mobile communications (GSM) technologies, Enhanced Data rates for GSM Evolution (EDGE) technologies, High Speed Packet Access (HSPA) technologies, etc.), and may be equipped with different power amplifiers (PAs) corresponding to different transmission paths. For example, one PA may need to have an industrial, scientific and medical (ISM)-band filter at the EDGE mode to prevent a 2.4 Gigahertz (GHz) signal from being coupled to another PA. However, this ISM-band filter is not needed in the GSM mode, and it will cause extra power loss in the GSM mode. Thus, a novel architecture is required for performing filtering control, in order to guarantee the overall performance of an electronic device.